By Philip Eden
The sixtieth anniversary of the Great London smog will no doubt be marked in all sections of the media next week. It was arguably the greatest meteorological disaster in the UK for some 250 years and led directly to the passing of the first Clean Air Act a few years later.
London and large parts of the Home Counties were blanketed with fog, heavily laden with toxic pollutants such as sulphur dioxide, nitrogen oxides and soot, from December 5 to 9 1952, visibility dropped below 20 metres for long periods, transport by road, rail, air and river was seriously disrupted, and dozens of sporting events were postponed. Pollution and extreme cold presented a deadly combination for people with chronic cardiovascular illnesses: most reference books quote a figure of 4000 deaths attributable to the smog, but this was the number above the normal death rate in the old London County Council area during the two weeks following the initial formation of thick fog. It does not include some 2000 additional deaths in adjacent counties (which at that time contained large portions of Greater London), nor does it include the prolonged period of above-average mortality which continued throughout the second half of December and into early January 1953. A more realistic number of deaths, therefore, lies somewhere between 6000 and 10,000.
The history of the Great London Smog is well documented, but the exceptional weather which occurred in other parts of the UK before, during, and after the foggy period is not. The November of 1952 was one of the coldest of the last century, and it culminated in a sequence of heavy snowfalls which affected much of the country. Worst hit were Wales, the Midlands and East Anglia; at Whipsnade in the Bedfordshire Chilterns level snow lay 10 inches deep on the 30th with drifts eight feet high, and in the Welsh valleys a train got stuck in a 10-foot drift. Remarkably low temperatures were also recorded, including -12C at Kielder in Northumberland and -15C at Dalwhinnie in Inverness-shire.
During London's smog episode, other parts of England were frosty but sunny. The fog layer in the Thames Valley was about 300-400 feet deep, and this meant that the hillier parts of the Home Counties such as the Chilterns and the North Downs poked through the blanket of fog into the clear air above. While Londoners groped around in 20 metre visibility for five days, the inmates of Whipsnade Zoo enjoyed 35 hours of sunshine.
After a brief milder interlude, cold weather returned with a vengeance on December 13, dumping 40cm of snow (drifts to 2.5m) at Bwlchgwyn in Denbighshire, and 18cm in Birmingham and the Black Country. This snowstorm was quickly followed by a northwesterly gale of unusual severity - a gust of 111 mph was measured at Cranwell in Lincolnshire which to this day remains the highest gust ever recorded at a lowland inland site in England - which caused widespread damage to buildings in eastern and midland counties.
By Philip Eden